Simulation of streaming electrification in a large core-form transformer winding

A network based approach for streaming electrification is extended to a full-scale power transformer structure. This model offers several improvements on the basic macroscopic electrification methodology first proposed by Roach and Templeton (1988). A complete range of flow conditions from laminar to fully turbulent is considered and the effects of power frequency electric fields are included. In addition, the influence of temperature is recognized and static potentials are calculated based on an appropriate leakage current matrix. A complete section of an eight-pass core-form power transformer winding has been examined under a variety of conditions. The results show that the size of the structure is critical and demonstrate the impact of entering charge from the cooling system. Static potentials in excess of 10 kV are shown to be possible under proper conditions with the potential distribution being highly dependent upon energization, flow rate and temperature